Question

Find the recursive formula for 18, 15, 12, 9, . .

Answer 1

Answer:
`a_(n)=a_(n-1)-3` ,
`n\geq 2`

Explanation:

`a_(1)` = 18

The common difference = -3

Therefore :

`a_(n)=a_(n-1)-3` ,
`n\geq 2`

check:

when n = 2

`a_(2)= a_(1)-3`

`a_(2)=18-3 = 15`